Firing mechanism for pneumatic gun

ABSTRACT

In the firing mechanism of a pneumatic gun that incorporates a bolt translatable from a bolt-open position to a bolt-closed position in response to compressed gas released during a firing operation, a latchable gas passageway restrictor is provided. The gas passageway restrictor is fixed in a latched position during the first portion of bolt movement from the bolt-open position to the bolt-closed position, and changes to an unlatched state during the last portion of bolt movement. While in the latched position the gas passageway restrictor reduces bolt thrust to a value preselected to not damage a jammed projectile that has not fully loaded into the gun. While in the unlatched state the gas passageway restrictor no longer reduces bolt thrust, thus ensuring that a fully loaded projectile is completely chambered. In addition, the gas passageway restrictor does not interfere with the flow of compressed gas provided to propel the projectile from the gun.

RELATED APPLICATIONS

This application is based on a prior co-pending U.S. provisional patent application Ser. No. 60/589,166, filed on Jul. 19, 2004, the benefit of the filing date of which is hereby claimed under 35 U.S.C. § 119(e), and the disclosure of which is incorporated herein in its entirety by this reference. This application also claims priority from prior U.S. patent application Ser. No. 11/073,772, filed on Mar. 7, 2005, entitled Velocity Limiter for Pneumatic Gun, the disclosure of which is incorporated herein in its entirety by this reference.

FIELD OF THE INVENTION

This invention relates to firing mechanisms for pneumatic guns in which the gun bolt moves the projectile being fired to a firing chamber in response to compressed gas released to fire the gun. More specifically, the invention incorporates a latchable gas passageway restrictor that reduces the thrust exerted by the bolt on the projectile during the first portion of movement toward the firing chamber. Additionally, the gas passageway restrictor does not restrict the flow of compressed gas provided to propel the projectile from the gun.

BACKGROUND OF THE INVENTION

Pneumatic guns, particularly guns configured to fire paintballs or metallic pellets, commonly include a bolt that is slidably translatable within the gun to alternately (1) move rearward to a bolt-open position and permit a new projectile to be loaded into the breech of the gun and (2) move forward to a bolt-closed position, where the bolt closes the passageway by which the projectile was loaded. As such a bolt moves forward to the bolt-closed position, it also acts to move the newly loaded projectile from the gun breech to the gun firing chamber, from which it will be propelled by the release of compressed gas. The position from which it will be propelled is sometimes referred to as the gun “firing chamber”, and hence the process of moving it forward from the initial loading position to the firing chamber can be referred to as “chambering”.

In one particular type of semiautomatic pneumatic gun, the compressed gas released to fire the projectile from the gun also serves to move the bolt forward from the bolt-open to the bolt-closed position, and thus move the projectile from the breech to the firing chamber. If the projectile is fragile, as is particularly the case for paintballs, the forward force exerted by the bolt on the projectile during the first portion of this forward movement should be limited to a value that will not damage the projectile if the projectile happens to jam in a partially loaded position. However, the force exerted near the end of the forward movement of the bolt must be sufficient to ensure that the bolt fully closes, particularly when an occasional oversized projectile resists being moved into the firing chamber.

Further, once the bolt is fully forward, the compressed gas should have a free path to reach the projectile being propelled. Otherwise, if the gas pathway is too restricted, the compressed gas will not reach the projectile at a sufficient rate to efficiently propel the projectile with the desired velocity.

Thus for pneumatic guns in which compressed gas serves to move the bolt forward to the bolt-closed position, there exists an unmet need for a means to restrict the thrust exerted by the compressed gas on the bolt during the first portion of bolt forward movement from the bolt-open position toward the bolt-closed position, and of then increasing the amount of thrust during the last portion of bolt movement as the projectile is being chambered. Further, the means selected should not restrict the flow of compressed gas to the projectile as the projectile is being propelled forward from the gun.

BRIEF SUMMARY OF THE INVENTION

The present invention is applicable to pneumatic guns that incorporate a bolt translatable from a bolt-open position to a bolt-closed position in response to compressed gas released during a firing operation in order to chamber a projectile before propelling it from the gun. In accord with the present invention, a firing mechanism is provided that includes a restrictable propulsion gas passageway and a latchable gas passageway restrictor assembly. The latchable gas passageway restrictor assembly includes a gas passageway restrictor that functions, while in the latched position, to reduce the thrust exerted by the bolt on the projectile being chambered during the first portion of bolt movement toward the bolt-closed position.

BRIEF DESCRIPTION OF THE DRAWING

In order to enable the reader to attain a more complete appreciation of the invention, and of the novel features and advantages thereof, attention is directed to the following description when considered in connection with the accompanying drawings, wherein:

FIG. 1 shows a gun according to the invention in a ready to fire state, with the poppet valve closed, the bolt in the open position and a paintball loaded into the gun.

FIG. 1A shows an enlarged view of major firing mechanism elements, with the gun in the same state as in FIG. 1.

FIG. 2 shows the gun early in a firing operation, with the poppet valve open, the gas passageway restrictor in the latched position and the reduced-thrust bolt piston urging the bolt forward.

FIG. 2A shows an enlarged view of major firing mechanism elements, with the gun in the same state as in FIG. 2.

FIG. 3 shows the gun later in a firing operation, with the bolt farther forward so that the piston contact face is just engaging the restrictor contact face.

FIG. 3A shows an enlarged view of major firing mechanism elements, with the gun in the same state as in FIG. 3.

FIG. 3B shows an enlarged view of the rear portion of the gun, with the gun in the same state as in FIG. 3.

FIG. 4 shows the gun later in a firing operation, with the gas passageway restrictor in the unlatched state and the full-thrust bolt piston urging the bolt forward at an increased level of thrust.

FIG. 4A shows an enlarged view of major firing mechanism elements, with the gun in the same state as in FIG. 4.

FIG. 5 shows the gun later in a firing operation, with the bolt forward in the bolt-closed position, the full-thrust bolt piston forward of the restrictable propulsion gas passageway and compressed gas flowing without restriction through the restrictable propulsion gas passageway and the bolt to propel the paintball forward.

FIG. 5A shows an enlarged view of major firing mechanism elements, with the gun in the same state as in FIG. 5.

FIG. 6 shows the gun near the end of the firing operation, with the poppet valve closed and the bolt spring moving the bolt, the bolt piston and the gas passageway restrictor rearward.

FIG. 6A shows an enlarged view of major firing mechanism elements, with the gun in the same state as in FIG. 6.

FIG. 7 shows a rear view of the gun to illustrate the gun cross section portrayed in the previous 13 figures.

DETAILED DESCRIPTION OF THE INVENTION

Shown in FIGS. 1, 2, 3, 4, 5 and 6 is a right-hand side cross sectional perspective view of one embodiment of a semiautomatic pneumatic gun 20 according to the invention. FIGS. 1A, 2A, 3A, 4A, 5A and 6A each show enlarged views of a central portion of gun 20 in a corresponding operating state. FIG. 1 shows gun 20 in a ready to fire state, and FIGS. 2-6 show it in successive stages of a firing operation. Referring to the rear view shown in FIG. 7, the cross section shown in FIGS. 1 through 6 can be seen to deviate slightly from a vertical planar cross section in order to better illustrate specific structural features of gun 20.

In FIGS. 2, 3, 4, 5 and 6 (and the associated enlarged views FIGS. 2A, 3A, 3B, 4A, 5A and 6A) arrows labeled “G” indicate major gas flows and arrows labeled “M” indicate major gun element movements of particular interest to the discussion herein.

Referring to FIGS. 1 and 1A, gun 20 has a frame 24 with a forward end 26 and a rearward end 28. Gun 20 is configured for the firing of paintballs. Within frame 24 is a paintball PB. Extending forward at forward end 26 is a gun barrel 32 that provides the firing chamber 34 from which paintball PB will be propelled when gun 20 is fired. Extending downward from frame 24 is a trigger frame 36 that includes a user-operable trigger 38.

Slidably accommodated into frame 24 is a cartridge housing 40. Cartridge housing 40 is closed rearwardly by a reservoir plug 44, and is retained within frame 24 by a rear gun plug 46. Gun 20 includes a firing mechanism 48. Most of the major components of firing mechanism 48 are contained within cartridge housing 40.

Bolt 50

Firing mechanism 48 includes a bolt 50. Bolt 50 is slidably translatable within a bolt chamber 52 that is provided partially by cartridge housing 40 and partially by frame 24. Bolt chamber 52 includes a front bolt chamber portion 54, and a rear bolt chamber portion 55 of larger diameter than front bolt chamber portion 54. Bolt 50 is illustrated in FIGS. 1 and 1A in a rearward, bolt-open position. Bolt 50 is slidably translatable between the bolt-open position and a forward, bolt-closed position that is shown in FIGS. 5 and 5A. Referring again to FIGS. 1 and 1A, a bolt spring 56 constantly urges bolt 50 rearward toward the bolt-open position. A resilient bolt forward buffer 58 is mounted externally on bolt 50 and serves to absorb shock as bolt 50 moves forward to the bolt-closed position.

Referring now to FIG. 1A, bolt 50 is partially penetrated from the rear by a bolt rear bore 62 that terminates forwardly in a rear bore face 64. Bolt 50 is partially penetrated from the front by a bolt front bore 66 that terminates rearwardly in a front bore face 68. Radially arranged and extending forward from rear bore face 64 through the front bore face 68 are a plurality of propulsion gas passageways 70.

Fixed to bolt 50 and extending rearward in bolt rear bore 62 is a bolt drive rod 74. In one embodiment bolt drive rod 74 is circular in cross section and coaxial with bolt 50. Rearward of rear bore face 64 bolt drive rod 74 has, in succession, a spacer section 76, a reduced-thrust bolt piston 78, and a full-thrust bolt piston 82 of successively larger diameters. Full-thrust bolt piston 82 has a piston rear face 83 that is rearwardly-directed, and a piston counterbalancing face 84 that is forwardly-directed and annular in shape. Bolt drive rod 74 has a piston contact face that is forwardly directed and that in one embodiment is provided by piston counterbalancing face 84. Bolt 50 and bolt drive rod 74 are preferably constructed of nonmagnetic material. A variety of plastic materials have proven satisfactory for bolt 50, and both aluminum and brass have proven satisfactory for bolt drive rod 74.

A spacer 86 surrounds spacer section 76, and is held by reduced-thrust bolt piston 78 against rear bore face 64. Spacer 86 is tapered so as to not obstruct the flow of compressed gas from bolt rear bore 62 into propulsion gas passageways 70. In one embodiment spacer 86 consists of a nonmagnetic material such as plastic, aluminum or brass. A resilient spacer buffer 87 is mounted externally on bolt drive rod 74 adjacent to spacer 86.

Referring to FIGS. 1 and 1A, extending upward from front bolt chamber portion 54 is a feed tube 88. Within front bolt chamber portion 54 adjacent to and in communication with feed tube 88 is a breech 90 for receiving paintballs as they are loaded into gun 20 from feed tube 88 when bolt 50 is rearward in the bolt-open position. In FIG. 1 breech 90 contains paintball PB just loaded into gun 20.

Poppet Valve 92

Referring to FIGS. 1 and 1A, firing mechanism 48 includes a poppet valve 92. Poppet valve 92 includes a valve body 94. Valve body 94 is fixed in position within cartridge housing 40 and is surrounded by external valve body o-rings 95F and 95R. Valve body 94 is fully penetrated axially by a valve body bore 96. Full-thrust bolt piston 82 fits slidably within valve body bore 96. In fluid communication with and terminating valve body bore 96 rearwardly is a valve seat 100. Valve body 94 is constructed of a material selected to provide high permeability for magnetic flux. Low carbon steel has been found suitable for the construction of valve body 94.

Extending rearwardly from valve body 94 within frame 24 is a gas reservoir 104 in fluid communication with valve seat 100. Gas reservoir 104 is also in fluid communication with an external source of compressed gas (not shown) that is connected to gun 20 at external source fitting 106. Compressed gas from the external source enters at external source fitting 106 and then flows in succession through a reservoir gas tube 108 and a reservoir inlet 110 to reach gas reservoir 104. Reservoir inlet 110 is seen best in FIG. 3B.

Referring to FIGS. 1, 1A and 3B, slidably translatable in gas reservoir 104 is a poppet 112 that in combination with valve body 94 provides poppet valve 92 for gun 20. Forwardly directed on poppet 112 is a valve seal 116 that is sealingly engageable with valve seat 100. A valve spring 124 constantly urges poppet 112 forward, toward a valve-closed position where valve seal 116 is engaged on valve seat 100. Poppet valve 92 is shown in this closed state in FIGS. 1A and 6A, and in an open state in FIGS. 2A, 3A, 3B, 4A and 5A.

Referring further to FIGS. 1 and 3B, poppet 112 has a poppet contact face 126 that is rearwardly directed. A poppet shaft portion 128 of poppet 112 extends rearwardly from poppet contact face 126 to terminate in a poppet drive piston 132 that is surrounded by an o-ring seal 136.

Gas reservoir 104 is sealed rearwardly by reservoir plug 44. Reservoir plug 44 is partially penetrated from the front by a poppet drive bore 144. Poppet drive piston 132 fits slidably within and, by virtue of o-ring seal 136, seals poppet drive bore 144.

A solenoid valve 148 is provided on gun 20. Solenoid valve 148 is a normally-open three-way solenoid valve of common commercially available construction. Solenoid valve 148 is controlled by an electronics assembly (not shown) contained in trigger frame 36 The electronics assembly is also of common commercially available construction. Trigger 38 is linked to the electronics assembly and permits the gun user to initiate a gun firing operation that briefly energizes solenoid valve 148.

Solenoid valve 148 has an inlet port 152, an outlet port 160 and a common port 164. Inlet port 152 receives compressed gas from the external source of compressed via an inlet gas tube 166 that provides fluid communication from external source fitting 106 to inlet port 152. Outlet port 160 is in fluid communication with the atmosphere. Common port 164 is in fluid communication with poppet drive bore 144 via a drive bore gas tube 168, a coupling 170 and a drive bore gas passageway 174. Coupling 170 and drive bore gas passageway 174 are seen best in FIG. 3B.

When solenoid valve 148 is in the normal, non-energized state, common port 164 is in fluid communication with inlet port 152 and hence with the external compressed gas source, with the result that compressed gas can flow through solenoid valve 148 to reach poppet drive bore 144 rearward of poppet drive piston 132. When solenoid valve 148 is energized, as occurs briefly during a firing operation, common port 164 is in fluid communication with outlet port 160 and hence with the atmosphere, allowing the compressed gas rearward of poppet drive piston 132 in poppet drive bore 144 to flow through solenoid valve 148 and escape to the atmosphere.

Poppet valve 92 functions in gun 20 as a piloted valve. The compressed gas provided to poppet drive bore 144 rearward of poppet drive piston 132 when solenoid valve 148 is not energized acts to urge poppet 112 forward and hence keep poppet valve 92 closed. During a gun firing operation solenoid valve 148 is energized briefly, allowing the compressed gas rearward of poppet drive piston 132 in poppet drive bore 144 to leak to the atmosphere. Poppet drive bore 144 is of larger diameter than the sealed diameter of poppet valve 92. As a result, after the gas pressure rearward of poppet drive piston 132 in poppet drive bore 144 drops sufficiently low, the pressure exerted by the compressed gas in gas reservoir 104 on poppet drive piston 132 then urges poppet 112 rearward, so that poppet valve 92 begins opening. As poppet valve 92 starts to open, the pressure in valve body bore 96 forward of poppet 112 rises, increasing the net rearward force on poppet 112 and causing poppet valve 92 to finish opening very rapidly. When solenoid valve 148 returns to the normal state later in the firing operation, compressed gas is again provided to poppet drive bore 144 rearward of poppet drive piston 132, thus encouraging poppet 112 to return to the valve-closed position.

Latchable Restrictor Assembly 178

Referring to FIG. 1A, firing mechanism 48 includes a latchable restrictor assembly 178. Latchable restrictor assembly 178 includes a restrictor latch 180 and a gas passageway restrictor 184. Restrictor latch 180 is in contact with and extends forward from valve body 94. In one embodiment restrictor latch 180 consists of a cylindrical magnet. Restrictor latch 180 is penetrated by a magnet bore 188. Restrictor latch 180 is preferably constructed of a magnetic material selected to provide high magnetic strength with low magnet volume. Commonly available rare earth magnets have been found to be suitable for use as restrictor latch 180. In one embodiment valve body bore 96 is slightly larger than magnet bore 188. Magnet bore 188 and valve body bore 96 in combination provide a restrictable propulsion gas passageway 192 in fluid communication with valve seat 100 that can slidably accommodate full-thrust bolt piston 82.

Valve body 94 and restrictor latch 180 are supported by a retainer sleeve 196. Retainer sleeve 196 is fixed in position within cartridge housing 40, and is sealed therein by a rear retainer sleeve o-ring 198 that is externally mounted on retainer sleeve 196. Bolt rear bore 62 fits slidably around retainer sleeve 196, and is sealed thereto when bolt 50 is forward in the bolt-closed position (illustrated in FIGS. 5 and 5A) by an external retainer sleeve o-ring 200. A resilient bolt rearward buffer 204 surrounds retainer sleeve 196 and serves to absorb shock as bolt 50 travels rearward. Valve body 94 is fixed in position within retainer sleeve 196, and is sealed therein by external valve body o-rings 95F and 95R. Retainer sleeve 196 is preferably constructed of a nonmagnetic material. Aluminum has been found suitable for the construction of retainer sleeve 196.

Gas passageway restrictor 184 has a forward restrictor portion 208 annular in shape. A restrictor tube portion 212 cylindrical in shape extends rearwardly from forward restrictor portion 208 and terminates in a restrictor pressure face 220. A restrictor bore 222 extends through gas passageway restrictor 184. Gas passageway restrictor 184 has a restrictor contact face that is rearwardly directed and that in one embodiment is provided by restrictor pressure face 220. Restrictor tube portion 212 is slidably translatable into and out of restrictable propulsion gas passageway 192, and is sealed therein by an internal valve body o-ring 224. Gas passageway restrictor 184 is constructed of a material selected to be magnetically attractive. Low carbon steel has been found satisfactory to construct gas passageway restrictor 184.

When gun 20 is ready to fire as shown in FIG. 1, gas passageway restrictor 184 resides in a latched position in close engagement with restrictor latch 180, and is held in this position by magnetic attraction with restrictor latch 180. As bolt 50 moves forward during a gun firing operation the piston contact face engages the restrictor contact face as shown in FIG. 3A. With further forward motion of bolt 50, gas passageway restrictor 184 unlatches and moves forward, away from restrictor latch 180 as shown in FIG. 4A. Gas passageway restrictor 184 is shown in the latched position in FIGS. 1A, 2A and 3A, and in an unlatched state in FIGS. 4A, 5A and 6A.

Full-thrust bolt piston 82 is larger than restrictor bore 222 and hence cannot pass through gas passageway restrictor 184. Spacer 86 is also larger than restrictor bore 222 and hence cannot pass through gas passageway restrictor 184. Thus gas passageway restrictor 184 slidably surrounds and is captive on reduced-thrust bolt piston 78.

Referring to FIG. 2A, reduced-thrust bolt piston 78 fits slidably through restrictor bore 222 and, while gas passageway restrictor 184 remains in the latched position, can function therein as a piston with a diameter identified by arrow DR. Referring to FIG. 4A, full-thrust bolt piston 82 fits slidably through restrictable propulsion gas passageway 192 and can function therein as a piston with a diameter identified by arrow DF while gas passageway restrictor 184 is in the unlatched state. As bolt 50 moves forward in response to compressed gas released during a gun firing operation, reduced-thrust bolt piston 78 functions as a piston to urge bolt 50 forward (FIG. 2A) until the piston contact face engages the restrictor contact face (FIG. 3A) and gas passageway restrictor 184 unlatches, after which full-thrust bolt piston 82 functions as a piston to urge bolt 50 forward (FIG. 4A) until piston rear face 83 is forward of restrictable propulsion gas passageway 192 as shown in FIG. 5A.

Referring to FIG. 2A, when poppet valve 92 opens during a firing operation, compressed gas enters restrictable propulsion gas passageway 192, where it reacts against various portions of bolt drive rod 74 and thereby serves to urge bolt 50 forward from the bolt-open position. While gas passageway restrictor 184 is in the latched position the portion of bolt drive rod 74 providing thrust is the reduced-thrust bolt piston 78. This occurs because the diameters of full-thrust bolt piston 82 relative to restrictable propulsion gas passageway 192, and of reduced-thrust bolt piston 78 relative to restrictor bore 222, are preselected to ensure that while gas passageway restrictor 184 resides in the latched position some of the compressed gas entering restrictable propulsion gas passageway 192 flows past full-thrust bolt piston 82 faster than it can flow past reduced-thrust bolt piston 78. As a result, compressed gas accumulates in the portion of restrictable propulsion gas passageway 192 forward of piston counterbalancing face 84 and rearward of restrictor pressure face 220.

When gas passageway restrictor 184 moves from the latched position shown in FIG. 2A to the unlatched state shown in FIG. 4A, the compressed gas pressure between counterbalancing face 84 and restrictor pressure face 220 is lost, and the portion of bolt drive rod 74 providing thrust now becomes full-thrust bolt piston 82.

Referring to FIGS. 2 and 2A, because the diameter DR of reduced-thrust bolt piston 78 is smaller than the diameter DF of full-thrust bolt piston 82, the force urging bolt 50 forward during the first portion of bolt movement from the bolt-open position toward the bolt-closed position is less than the force provided later. Importantly, the gun designer can preselect the diameters and lengths of these and associated firing mechanism components to achieve the desired amount of bolt thrust that will occur during early and later portions of bolt forward movement, and the position of the bolt at which the transition from reduced to full thrust will occur. More specifically, the gun designer can preselect the diameter of reduced-thrust bolt piston 78 to achieve a force sufficient to move bolt 50 and paintball PB forward, but not so much force that a paintball is damaged even if it happens to jam before it has moved fully down from feed tube 88 into breech 90. And the gun designer can preselect the diameter of full-thrust bolt piston 82 to achieve a force sufficient to ensure that bolt 50 will continue completely forward to the bolt-closed position it is approaching in FIG. 4, and has reached in FIG. 5, even when an occasional oversized paintball resists being moved forward into firing chamber 34

Velocity Limiter 230

Referring to FIGS. 1 and 3B, firing mechanism 48 includes a velocity limiter 230. Velocity limiter 230 is slidably translatable within gas reservoir 104. In one embodiment velocity limiter 230 has a first limiter section 234, and a second limiter section 238 of smaller diameter than first limiter section 234. Second limiter section 238 includes at the rear a limiter stop section 240 of larger diameter than poppet drive bore 144. First limiter section 234 fits slidably within gas reservoir 104. Longitudinally, velocity limiter 230 is penetrated by a first bore 242 that fits slidably around poppet shaft portion 128, and partially from the front by a second bore 246. Second bore 246 is of greater diameter than first bore 242 and fits slidably around valve spring 124.

Velocity limiter 230 has a first discharge face 250, and a second discharge face 254, both oriented toward valve seat 100 and annular in form. Valve spring 124 impinges on second discharge face 254 to urge velocity limiter 230 rearward. Velocity limiter 230 has a first driven face 260, and a second driven face 264, both oriented away from valve seat 100 and annular in form. On first discharge face 250 is a limiter contact face 268 that is engageable with poppet contact face 126 as velocity limiter 230 slides toward valve seat 100.

As can be understood from the foregoing, velocity limiter 230 divides gas reservoir 104 into a driving portion 272 and a discharge portion 276. Driving portion 272 is in fluid communication with the external source of compressed gas via reservoir inlet 110, reservoir gas tube 108 and external source fitting 106. Discharge portion 276 is in fluid communication with valve seat 100. The relative size of these two portions of gas reservoir 104 varies as velocity limiter 230 moves during a firing operation, as can be seen in the successive firing operation stages illustrated in FIGS. 2, 3, 4, 5 and 6.

When gun 20 is ready to fire, velocity limiter 230 resides rearward in a limiter at-rest position illustrated in FIG. 1, with limiter stop section 240 in contact with reservoir plug 44. When poppet valve 92 opens during a firing operation as described above, compressed gas in discharge portion 276 flows out through valve seat 100, causing the gas pressure within discharge portion 276 to decrease. As a result, the force exerted by the compressed gas within driving portion 272 on first driven face 260 and second driven face 264 serves to urge velocity limiter 230 toward valve seat 100 as illustrated by arrows labeled “M” in FIGS. 2, 3 and 4, compressing valve spring 124. As velocity limiter 230 travels forward in this manner, it engages with poppet contact face 126 as shown in FIG. 5 and then moves poppet 112 forward, thus closing poppet valve 92.

The fit of velocity limiter 230 relative to gas reservoir 104 and to poppet shaft portion 128 is preselected by the gun designer to ensure that compressed gas can leak from driving portion 272 to discharge portion 276. As a result, once poppet valve 92 closes so that compressed gas is no longer able to escape from discharge portion 276, compressed gas leaking from driving portion 272 to discharge portion 276 will make the gas pressures in the two portions more equal, and compressed valve spring 124 will be able to urge velocity limiter 230 away from valve seat 100 and back to the limiter at-rest position shown in FIG. 1 in time for the next firing operation. FIG. 6 illustrates this rearward movement of velocity limiter 230.

Operation

Referring to FIGS. 1 and 1A, gun 20 is shown in a ready to fire state. At the beginning of a firing operation the electronics assembly in trigger frame 36 briefly activates solenoid valve 148, allowing compressed gas rearward of poppet drive piston 132 in poppet drive bore 144 to escape.

Referring to FIGS. 2 and 2A, where major gas flows are identified by arrows labeled “G”, poppet 112 moves rearward in response to the drop in gas pressure rearward of poppet drive piston 132 in poppet drive bore 144, opening poppet valve 92. With poppet valve 92 open, compressed gas flows from gas reservoir 104 into restrictable propulsion gas passageway 192. Some of this compressed gas flows past full-thrust bolt piston 82, causing pressure to build up between piston counterbalancing face 84 and restrictor pressure face 220.

Reduced-thrust bolt piston 78 now reacts to the compressed gas present in restrictable propulsion gas passageway 192, thereby urging bolt 50 forward as indicated by the arrow labeled “M” in FIG. 2A and compressing bolt spring 56. As bolt 50 and bolt drive rod 74 continue to move forward, the piston contact face (provided in one embodiment by piston counterbalancing face 84) impinges on the restrictor contact face (provided in one embodiment by restrictor pressure face 220). This stage of the firing operation is shown in FIG. 3A.

The forward motion of bolt 50 and bolt drive rod 74 continues beyond the point illustrated in FIG. 3A, unlatching gas passageway restrictor 184 from restrictor latch 180 as illustrated in FIG. 4A and allowing it to slide forward to contact spacer buffer 87 as shown in FIG. 5A.

Referring further to FIG. 4A, with gas passageway restrictor 184 now in this unlatched state, the compressed gas between piston counterbalancing face 84 and restrictor pressure face 220 is gone. Full-thrust bolt piston 82 now reacts to the compressed gas present in restrictable propulsion gas passageway 192 to urge bolt 50 forward with greater force. This increased forward force helps to ensure that bolt 50 will continue completely forward to the bolt-closed position it is approaching in FIG. 4, and has reached in FIG. 5, even when an occasional oversized paintball resists being moved forward into firing chamber 34.

As bolt 50 continues to move forward beyond the position shown in FIG. 4A to the bolt closed position shown in FIGS. 5 and 5A, full-thrust bolt piston 82 clears restrictable propulsion gas passageway 192. Restrictable propulsion gas passageway 192 now provides an open, unrestricted path for the passage of compressed gas. The compressed gas in discharge portion 276 of gas reservoir 104 now flows in succession through valve seat 100, restrictable propulsion gas passageway 192, bolt rear bore 62, propulsion gas passageways 70 and bolt front bore 66 to reach paintball PB in firing chamber 34 and thus propel paintball PB forward through barrel 32. This gas flow is indicated schematically by the arrows labeled “G” in FIG. 5A.

As compressed gas now flows rapidly from discharge portion 276 of gas reservoir 104, velocity limiter 230 moves forward to engage poppet contact face 126 as shown in FIG. 5. Velocity limiter 230 continues to move forward, thereby moving poppet 112 forward to the poppet valve closed position shown in FIG. 6. With the flow of compressed gas into restrictable propulsion gas passageway 192 thus cut off, bolt 50, bolt drive rod 74 and gas passageway restrictor 184 are able to move rearward in response to the urging of bolt spring 56 as illustrated in FIGS. 6 and 6A. As this rearward movement is completed, gun 20 is returned to the ready-to-fire condition seen previously in FIG. 1.

Thus it can be seen that a latchable restrictor assembly as disclosed herein provides two types of advantage. First, it modulates bolt thrust as the bolt moves forward during a firing operation. Thrust is weaker during the first portion of bolt travel, minimizing the risk of damaging the projectile being chambered. And thrust is stronger during the last portion of bolt travel, ensuring that the bolt closes fully and that the projectile is fully chambered. Second, a large unrestricted gas passageway is provided for compressed gas to flow to the projectile being propelled, thereby making most effective use of the available compressed gas and improving the firing performance of the gun.

Although the present invention has been described in connection with the preferred form of practicing it and modifications thereto, those of ordinary skill in the art will understand that many other modifications can be made to the present invention within the scope of the claims that follow. By way of example but not limitation, a mechanical latch might be substituted for the magnetic latch described herein. Accordingly, it is not intended that the scope of the invention in any way be limited by the above description, but instead be determined entirely by reference to the claims that follow.

It is to be appreciated that the various aspects and embodiments of the invention described herein are an important improvement in the state of the art, especially for paintball guns. Although only an exemplary embodiment has been described in detail, various details are sufficiently set forth in the drawings and in the specification provided herein to enable one of ordinary skill in the art to make and use the invention(s), which need not be further described by additional writing in this detailed description. Importantly, the aspects and embodiments described and claimed herein may be modified from those shown without materially departing from the novel teachings and advantages provided by this invention, and may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. In particular, while the foregoing description describes propulsion of paintballs, one skilled in the art can easily configure guns according the invention to propel other projectiles such as metallic pellets.

Therefore, the embodiments presented herein are to be considered in all respects as illustrative and not restrictive. As such, this disclosure is intended to cover the structures described herein and not only structural equivalents thereof, but also equivalent structures. Numerous modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention(s) may be practiced otherwise than as specifically described herein. Thus, the scope of the invention(s), as set forth in the appended claims, and as indicated by the drawing and by the foregoing description, is intended to include variations from the embodiment provided which are nevertheless described by the broad interpretation and range properly afforded to the plain meaning of the claims set forth below. 

1. A firing mechanism for a pneumatic gun, said firing mechanism comprising a bolt, a bolt drive rod, a restrictable propulsion gas passageway and a latchable restrictor assembly, said latchable restrictor assembly comprising a restrictor latch and a gas passageway restrictor, said gas passageway restrictor comprising a restrictor pressure face and a restrictor contact face, said bolt drive rod comprising a reduced-thrust bolt piston and a piston contact face, said piston contact face engageable with said restrictor contact face, said reduced-thrust bolt piston slidable into said restrictable propulsion gas passageway, said gas passageway restrictor slidably surrounding said reduced-thrust bolt piston and captive thereon.
 2. The apparatus of claim 1 wherein said restrictor latch further comprises a ring magnet and said gas passageway restrictor is constructed of a magnetically attractive material, whereby said gas passageway restrictor is retained in a latched position by magnetic attraction between said restrictor latch and said gas passageway restrictor.
 3. The apparatus of claim 1 wherein said firing mechanism further comprises a bolt return spring.
 4. A firing mechanism for a pneumatic gun, the pneumatic gun for firing projectiles by release of compressed gas as a propellant, said firing mechanism comprising a bolt, a bolt drive rod, a restrictable propulsion gas passageway and a latchable restrictor assembly, said bolt slidably translatable between a bolt-open position and a bolt-closed position, said latchable restrictor assembly comprising a restrictor latch and a gas passageway restrictor, said gas passageway restrictor comprising a restrictor pressure face and a restrictor contact face, said bolt drive rod comprising a reduced-thrust bolt piston, a full-thrust bolt piston and a piston contact face, said reduced-thrust bolt piston smaller in diameter than said full-thrust bolt piston, said reduced-thrust bolt piston and said full-thrust bolt piston slidable into said restrictable propulsion gas passageway, said gas passageway restrictor slidably surrounding said reduced-thrust bolt piston and captive thereon, said gas passageway restrictor residing, when said pneumatic gun is ready to fire, in a latched position, said reduced-thrust bolt piston reactive, when said gas passageway restrictor is in said latched position, to compressed gas released during a firing operation to thereby urge said bolt from said bolt-open position toward said bolt-closed position, said piston contact face engageable with said restrictor contact face as said bolt moves toward said bolt-closed position to urge said gas passageway restrictor from said latched position to an unlatched state, said full-thrust bolt piston reactive, when said gas passageway restrictor is in said unlatched state, to the compressed gas released during a firing operation to thereby urge said bolt toward said bolt-closed position.
 5. The apparatus of claim 4 wherein said restrictor latch comprises a ring magnet and said gas passageway restrictor is constructed of a magnetically attractive material, whereby said gas passageway restrictor is retained in said latched position by magnetic attraction.
 6. The apparatus of claim 4 wherein said firing mechanism comprises a bolt return spring for urging said toward said bolt-open position.
 7. A firing mechanism for a pneumatic gun, said firing mechanism comprising a bolt, a bolt drive rod, a restrictable propulsion gas passageway and a latchable restrictor assembly, said latchable restrictor assembly comprising a restrictor latch and a gas passageway restrictor, said gas passageway restrictor comprising a restrictor pressure face, a restrictor contact face and a restrictor bore, said bolt drive rod comprising a reduced-thrust bolt piston and a piston contact face, said piston contact face engageable with said restrictor contact face, said reduced-thrust bolt piston slidable into said restrictable propulsion gas passageway, said gas passageway restrictor slidably surrounding said reduced-thrust bolt piston and captive thereon, said gas passageway restrictor residing, when said pneumatic gun is ready to fire, in a latched position whereat compressed gas released during a firing operation reacts on said reduced-thrust bolt piston to urge said bolt from said bolt-open position toward said bolt-closed position, said gas passageway restrictor retained in said latched position by magnetic attraction between said restrictor latch and said gas passageway restrictor.
 8. The apparatus of claim 7 wherein said restrictor latch comprises a ring magnet and said gas passageway restrictor is constructed of a magnetically attractive material.
 9. The apparatus of claim 7 wherein said firing mechanism comprises a bolt return spring for urging said toward said bolt-open position. 